Surface mount device (SMD) packages can be used to house semiconductor devices and directly connect them to printed circuit boards (PCBs). A large number of electronic circuit designs have been using the SMD packages due to various benefits that the surface mount devices can offer. For example, in military and space applications (e.g., high performance vehicles, aircraft, space shuttles and satellites) where high reliability is imperative, SMD packages can provide the robustness necessary in extreme or harsh environments, while offering benefits such as smaller size, lighter weight, and excellent thermal performance.
However, the popularity of the SMD packages has been somewhat hindered by the coefficient of thermal expansion (CTE) incompatibility between different materials used in different portions of a case of a SMD package, and between the SMD package and the PCB material. For example, a conventional SMD package may include Kovar® sidewalls and a ceramic base. While Kovar® and ceramic materials have substantially matched CTEs at room temperature, their CTEs start diverging drastically as temperature increases. Thermal stress can accumulate between the sidewalls and the base as they expand and contract during fabrication processes and thermal cycles. In addition, when a conventional SMD package is mounted onto a PCB, a CTE mismatch between the conventional SMD package and the PCB may introduce mounting stress to the SMD package. These stresses can cause fatigue and cracking of the SMD package, which in turn can result in hermeticity loss of the SMD package and damage to the semiconductor devices and circuitry inside the SMD package.
Accordingly, there is a need to overcome the drawbacks and deficiencies in the art by providing a semiconductor package, such as a SMD package, that can substantially reduce fatigue and cracking of the semiconductor package due to thermal and mounting stresses.